There is a lemonade stand where customers can buy one lemonade at a time for $\$5$ and pay with a $\$5$, $\$10$, or $\$20$ bill. It is necessary to return the correct change to each customer so that the net transaction is completed successfully with a total payment of $\$5$. Note that no change is available initially.

Given an integer array, bills, where bills[i] represents the bill paid by the $i^{th}$ ...